Electric cable.



V. P. VON PINDTERSHOFEN.

ELECTRIC CABLE.

APPLICATION FILED JAN. 27; 190e.

Patented Sept. 3, 1912.

1 MMWWWM l Mwmuummmmmll Inl@ Aals VCTOR PIND'TER von PINDTERSHOFEN, OF WIENER-NEUSTADT, AUSTRIA-HUNGARY.

' ELECTRIC CABLE.

Specification 'of Letters Patent.

Patented sept.. 3, 191e.

\ Application led January 27, 1909. -Serial No. 474,631.

To aZZ whom t may concern Be it known that L; Vic'Ton- PrND'rEn voN' PnsDTERsHorEma subject yof the Austro- Hungarian Emperor, and residing at lViener-Neustad-t, Austria-Hungary, have invented certain new and useful lmprove? ments in Electric Cables,.of. which the following is a specification.v

vantages which only eXce tionally, and also' only orrelatively small istances, admit ofv the employment of suchv high tension cables instead of aerial lines. Especially does it vappear impossible, however, to conduct currents of still higher tensions with such cables, since every solid insulatingmaterial admits of the passage of Weak currents at very high 'tensionsx This leakage of the current increasesl with the length ot the cable itself, so that frequently for this reason alone long high tension conductors were found to be uneconomical. A further important disadvantage of such cables, which. are fed almost without Vexception with alternating currents is the very great capacity of the same in consequence oi the high dielectric constant of the insulating material. Apart from these defects' the weight.

of such a cable covered withA solid insulating material is not small and the cost of manufacture is relatively large. For all these reasons it appears impossible in practice to employ ca es, in which the conductors are surrounded with solid insulating material, for long distances for supplyingy largel currents at very hi h tensions, or to manufacture usable cab es for tensions higher than about 20,000 volts.

In the high tension cable accordin to the present invention dry air is employe -as insulation, the conductors being arranged in an insulating, closed protecting tube. The dr air is on the one hand a very good insu ator, and on the other hand, even atl very y high tensions, only ,a very small, scarcely measurable capacity results. For increasing the insulation still further, according to the present invention each conductor is surrounded at some dist-ance from it with an additional insulating,`solid partit-ion in the form of a concentric tube or also, according to the degree of insulation in each instance, with two or more tubes, which likewise are inserted one in another concentric-ally with an air space between them. In order to keep the conductors in the centers of the tubes they are held by insulating supports in the form. of beads Aor small disks which are arranged in rows at intervals on the emductors.` Owingto'the arrangement of the insulating tubes a combined insulation by means of air and solid insulating material is obtained, a veryrhigh degree of certainty against break-down being obtained, Withoutl increasing the capacity. l The arrangement of two or more concentric insulating tubes with anvair space'be- 75 tween them is employed for very high tensions. Besides 'the vcombined insulation by dr`y air and the concentric insulating tubes,

in accordance with the present invention for certainly preventing the current leaking an additional means is employed, namely the,AX path which the current' tends to take Whenf' leaking from the conductors along the solid insulating material is` made very long and of as `small cross-section as possible. Forfgwf, this purpose the insulating beads or small 1 disks, which hold the conductors in the centers of t-he insulating tubes, are displaced longitudinally relatively to the supports o'r/f holders whichare outside the insulating tubes and which carry the insulating tubes of the individual lconductors in the principal protecting tube.l When several con-` centric tubes are employed' around each'conductor the bars or holders which keep the individual concentric tubes at the proper distance from one another are also-displaced relatively to the outside supports ot the in- ,ef sulating tubes. In this manner a step-like path in the solid material is formed. Fur- 100 ther, the insulating tubes of the individual conductors can be held at central longitu- Idinal bars by shackles, supporters, suspenders or the like arranged at intervals 'and displaced yrelatively to one another` 105 alon the individual insulatin tubes, which longitudinal bars are carrie by separate frames supported. against lthe interior wall of the exterior protecting tube. By this arrangement the path vfora possible leak- 11o age current alongthe solid insulating ma terial is made exceedingly long but is of small breadth and has a small cross-sectional area. v

ln orde that the invention may be clearly understood 'reference will be made to the accompanying drawing in which several embodimentsfare represented by way of example, and in which:

Figure 1 is a vertical section, and Fig. 2 a longitudinal section, partly in elevation, of a cable in which only one concentric insulating'tube is provided around each conductor within a common outer protecting tube; Figs. Band 4 are like views, respectively, of a cable comprising two concentric insulating tubes surroun .ing a conductor; Fig. 5 is. a longitudinal section, partly in eievatiomof a cablel having concentric insulating spiral windings formlng tubes arranged around the conductor,whereas Fig. 6 is a cross-section through a cable in which each conductor is surrounded bv two concentric insulating tubes, and Fig.

7 is a sectional perspective view ot the latter cable showing the manner in which the insulating tubes are supported in the outer protecting tube. v

Referring to the drawing, on the metalli:

n conductor 1 insulating beads or disks 2 yare arranged in rows at considerable distances from one' another and hold the conductor tree in the center of the insulating tube 3. ln this manner the conductor is surrounded by air with the exception of the exceedingly vsmall places which are covered by the disks '2. T he insulating tubes 3, 4 and I5 (Figs.

1 and 2) surrounding the conductors 1 and arranged at intervals from one another, and which are preferably hermetically sealed their entire length to prevent the admission ot moisture, are arranged 1n an Insulatlng,

protecting tube 6 which surrounds the insulating tubes at a short distance from them and is likewise closed air-tight. 1n this manner air insulation is also provided outside the insulating tubes. '1n order to hold the insulatin tubes 8,4 and 5 free in the protecting tu )e 6, the same are attached by means of insulating supporters or suspend-` ers 7 to insulating bars 8 which are arranged at intervals in the center longitudinally of the cable and are carried by separate frames 9 ofinsulating material. 1n the constructional form represented the frames 9 have the :torni of tripods as clearly shown in Figs. 1, 2 and 7. For obtaining the space between the insulating tubes 4insulating support-ing members 10 are inserted. As the contact between the solid insulating material and the conductor is limited to only individual short places, on the one hand a very high insulation of the conductor is obtained'and on the other hand the capacity is kept low. Only the short places of the insulating tube when? the disks 2 are located have an exceedingly weak charge wh1ch, however, exercises no further reaction on the conductor, since the charge cannot continue farther to the outside-through solid insulating material. A further advantage of the described arrangement consists lin the form of the long path in theA solid material which the current would have to take to pass from one conductor to the other or to earth. For leaking to earth, for example, the current. would have to pass by way of the disk 2, then along the wall of the tube in question, and by way of the member 10, in order to pass from the bar 8 by way of the tripod 9 to the outer protecting tube 6. The current does not at once tend to'jump across the air space and circumvent this long path along or in. solid insulating material, particularly. when this lair space is very dry.

The insulating tubes 3, 4 and 5, as well as the exterior protecting tube 6,'are prefer'- ably made of paper or like material'which is soaked with a mixture of resin, wax, etc.

1n order to have a certain amount of` certainty that no defective `places existin-Ht-he walls ot the tubes, the tubes are made of two superposed layers preferably stuck together by a fusible insulating' material which fills up the gap between the two layers. The tubes may comprise separate pieces of tube placed in a row longitudi` nally, as clearly shown in Figs. 2 and 4, or

they may consist ot' two layers ofv spiral rial (Fig. 2).

For very high tensions, inV accordance' with the present invention two or ymore tubes 11 and 12 (Figs. 3 to 6) are employed concentrically surrounding the conductors with an intermediate air space, the distance between which tubes is maintained by insu- .lating rings 13. 1n the form represented iu Figs. 3 and 4, in which the tubes 11 and 12 each consists of two layers of separate tubular pieces placed in rows, the rings 13 are stuck on the joints 14 of the inner double tube 11, whereas the supporters 7 and the members 10 surround the joints 15 of the exterior double tube 12. Here again the individual joints 14 and 15 are displaced relatively to one another longitudinally, so thata very long step-like path is formed for a current passing along the solid insulating inaterial and simultaneously the capacity of the cable is kept low. In like manner in the iso form ,represented in Fig. 5, which spiral windings are employed to form the tubes, the rings 13 are displaced relatively to the Suspenders or supporters 7. The exterior protecting tube 6 likewise consistsortwo superposed layers stuck together.- If the latter are composed of individual pieces of tube, as represented in Fig. 2, the joints 16 of the, inner and outer layers are relatively displacedv and strengthened by means of insulating rings or sleeves 17 alixed to them. The protecting tube 6 is surrounded along its entire length with a protecting layer 18 of tar, asphalt, wood-cement or the like and with a bandage soaked with these materials.'L

For conveying and erecting the ldescribed high tension cable the insulating tubes are pushed together in larger or smaller lengths and stuck together tightlyby heated insulatiig material, for example in a length of 15 to 2O meters.. Thereupon the insulating tubes after being fastened to the longitudiiialbars provided with the frames ortripods are inserted into the exterior protecting tube assembled in like lengths, and this is sealed at the ends to prevent admission of moist air. For erecting the cable on the spot, on each portion of cable at the one end the exterior layer and at the other end the interior layer of each double tube, both insulating tubes and also protecting tube, is laid bare, so that at the ends of the portions of cable the tubes can be inserted one in another up to the joints, the heated insulating material being continuously employed, so that the form of cable clearlv shown 1n Figs. 2 and 4 is obtained. In this manner one continuous homogeneous construction, and an equally high insulation is obtained in the high tension cable along its entire length.

The wires provided with the bead or disk insulatorsare Idrawn into the 'insulating tubes in known manner. For this purpose iron wires may be placed into the insulating tubes of each portion of cable from the outset, for example.

What I claim as my invention and desire to secure by Letters Patent is:

1. High tension cable, characterized by the individual conductors being arranged in insulating tubes with a concentric intermediate air space and being mounted in com- -mn with an exterior insulating closed protecting tube at a distance from 'the inner wall ofthe same, whereby a combined air and material insulation is obtained and high capacity of the cable is avoided.

2. In electric cables, the combination with individual conductors, insulating tubes concentrically arranged relatively to the respec tive conductors, and supports separating the conductors from the tubes, whereby anl intermediate air space is formed between the conductor and tube; of a common exterior protecting tube and supports for spacing the exterior tube from the insulating tubes, the said last-named supports being displaced longitudinally withregard to the supports separating the conductors from the insulating tubes, whereby an elongated path is obtained for any current leakage'.

3. In electric cables, the combination with individual conductors, insulating tubes concentrically arranged relatively to said conductors, and supports separating the conductors from the tubes, whereby anl intermediate air space is formed between' the 'conductor and tube, of a common exterior protecting tube and supports for spacing the exterior tube from the insulating tubes, the

said last named supports being displaced longitudinally with regard tothe supports,

separating the'conductors from the insulating tubes,'whereby an elongated path is. obtained for*any current leakage.

4. In electric cables, the combination with individual conductors, an insulating tube concentrically arranged around each conductor, means holding apart the tube| from the conductor and forming a concentric airspace between conductor and tube, this insulating tube consisting of two tightly' telescoped tubes made of sections, the joints of which are longitudinally displaced with regard to eachother.

5. In electric cables, the combination with individual conductors, an insulatin tube concentrically arranged around eac con ductor, means holding apart the tube 'from the conductor and forming a concentric airspace between conductor and tube, another insulating tube concentrically around the latter, means holding this tube concentri# cally with regard to the first one and forming an insulating air-space, whereby the insulating` tubes consist of two tightly telescoped tubes; said tubes bein made of sec'- tions, the joints of which areongitudinally displaced with regard to one another. 6. In electric cables, the combination with individual conductors, an insulatin tube concentrically arranged around eac conductor, and means holding apart the tube from the conductor and forming a concentric air-space between conductorv and tube; this insulating tube consisting of two tightly telesco ed tubes of several lengths, the'outer insulating tube being surrounded by a supporting ribbon at the one side and by an inserted insulating wedge at the other side or mechanically and electrically reinforcing the joint and obtaining a larger resistance.

7. In electric cables, the combination with individual conductors, an insulating tube concentrically arranged around each conductor, means holding apart the tube from' latter, and sleeves to hold this tube ,concentrically with regard to the other; these sleeves being arranged lto tightly surround the inner and outer (layers of the inner insulating tube for mechanically and electrically reinforcing the joint and obtaining a larger resistance.

8.' In electric cables, the combinationof a plurality of individual conductors, insulating tubes concentrical-ly arranged relatively to said conductors, supports holding apart the conductors from the 4tubes and forming an air-space between conductor and tube, a common outer protective tube, and supports forming a space between the outer tube andv the insulating tube; the outer protective tube consisting of two layers of tightly telescoped tube lengths, the jolnts being longitudinally displaced with regard to each other and sleeves being arranged around the joints for reinforcement.

9. ln electric cables, the combination with individual conductors, insulating tubes concentrically arranged relatively to therespective conductors, and supports separating the conductors from the tubes, whereby an intermediate air space'is formed between each conductor and tube; of a common eX- terior protecting. tube, supports for spacing the exterior tube from the insulating tubes, amiddle bar with spacing members about which said insulating tubes are disposed, insulating supporting ribbon binding together the insulating tubes, spacing members and aceptas middle bar for the purpose of spacing the single tubes from each other and from the bar, and an insulating star for holding thi-s bar in the midst ofthe tube and for holding the insulating tubes apart from the outer protective tube.

l0. ln electric cables, the combination with individual conductors, insulating tubes concentricallyl arranged relatively to said conductors, .and supports separating the oo nductors fromthe tubes, whereby an intermediate air space is formed between the conductor and tube; of a common exterior protecting tube and supports for spacing the exterior tube from the insulating tubes; the several insulating tubes consisting of single telescoped tube-lengths with longitudinally displaced joints, the joints of the different tubes being also longitudinally displaced with regard to each other; there being provided a middle bar for holding the tu es, insulating supporting ribbons bindin'v the tubes to the bar, surrounding the longitudinally displaced joints of the insulating tubes for the purpose of reinforcement, and means for holding the bar and therebv the insulating tubes in the midst of the outer protective tube.

ln testimony whereof, l affix my signature lin the presence of two witnesses.

VlClltlR PIND'lER VON PINDTERSHOFEN. Witnesses:

A ROBERT W. HEINGARTNER,

AUGUST Fussell. 

